On Thursday, President Barack Obama took to the pages of the New York Times to remind Americans of NATO's continued relevance:

"For more than six decades, Europeans and Americans have stood shoulder to shoulder because our work together advances our interests and protects the freedoms we cherish as democratic societies."

After the Soviet Union collapsed, NATO's purpose dissolved. Nevertheless, America’s embrace of "collective security" has since morphed into a rationale for subsuming Europe’s military autonomy within a U.S.-dominated security framework. Take, for example, the Clinton administration's promotion of the European Union’s move toward military self-reliance, through the European Security and Defense Policy. That support, however, was conditioned by what Secretary of State Madeleine Albright called the "three D's": no decoupling of U.S. and European decision making, no discriminating against non-EU NATO members, and no duplicating NATO's operational planning system or command structure.

President George W. Bush also signaled Washington's support for improvements to Europe's military capabilities, so long as it took place under NATO's purview. In fact, when the largest European states—Germany and France—opposed America's intervention in Iraq, they proposed the establishment of an independent military headquarters, with an independent planning capacity. In reponse, U.S. Ambassador to NATO Nicholas Burns described the effort as "the greatest threat to the future" of the trans-Atlantic alliance.

Interestingly, many U.S. leaders bemoan the relatively paltry sums their Western allies spend on defense. Compared to the United States, which this year spent roughly five percent of its $15 trillion dollar GDP on military-related expenditures, Britain, France, and Germany spent as little as 2.6 percent, 2.1 percent, and 1.15 percent of their GDP on defense, respectively. But these deficiencies should be expected: multi-national alliances like NATO encourage large member states to bear a disproportionate share of the common defense. Since smaller states know that larger states will provide the collective good of military protection, smaller states devote a smaller portion of their resources toward defense and still feel safe.

That compelling assessment of the behavior of small states still falls short of explaining why larger states choose to bear a disproportionate share of the common defense. Luckily, one school of thought within International Relations—hegemonic stability theory—may provide an answer. It posits that a stable international system is most likely to transpire when a single dominant state acquires a preponderance of global power. Therefore, today, in the absence of a preeminent Soviet rival lurking over the European landmass, a weakened NATO, in the estimation of U.S. leaders, may ostensibly secure America's hegemonic interests by derailing potential challenges to U.S. primacy.

Hegemony, however, comes at a high cost. Attempts to retain it can even hasten hegemonic decline. Given the immediate threat facing NATO's prestige in Afghanistan, as well as America's soaring budget deficits at home, the current state of the trans-Atlantic alliance should throw into question the wisdom of assuming inordinate economic and military burdens to subsidize the protection of European welfare states.